The present invention relates to encoding and sensing of information or configuration, and, especially, to encoded syringes, to injectors for reading encoded syringes, to injector systems including encoded syringes and to methods of encoding and sensing syringe information.
Critical parameters of an injection procedure are determined by a number of variables, including, for example, syringe diameter, syringe length, syringe material and fluid composition/concentration. Among the affected injection procedure parameters are fluid volume delivered, flow rate, fluid pressure, and limits of injector piston travel. In current injector systems, syringe size/volume is generally determined either (1) manually by action of an operator who enters the syringe size/volume or type into the injector software, or (2) automatically by means of switches on the injector head which are mechanically coupled to raised or sunken elements on the syringe. See, for example, U.S. Pat. Nos. 5,741,232, 6,090,064 and 5,873,861, assigned to the assignee of the present application, the disclosures of which are incorporated herein by reference. In U.S. Pat. No. 5,873,861, the presence or absence of one or more of detents provides a code that is representative of syringe configuration.
Constraints of current mechanical and electrical design, however, limit the number of such automatic detection switches. Indeed, only limited syringe configurations are automatically detected with present systems. Additionally, failure of certain moving mechanisms is also a problem. For example, spillage or leakage of contrast media can result in the failure of certain mechanisms. Moreover, certain electrical and mechanical encoding systems can significantly increase manufacturing costs of a syringe and/or injector. Other currently available methods of encoding and sensing syringe configuration include the placement of bar codes and corresponding sensors upon the syringe and injector, respectively, as disclosed in U.S. Pat. No. 5,997,502. Bar code systems, however, suffer from some of the same problems as the electromechanical systems discussed above.
As used herein, the term “syringe configuration” is used to encompass all information about a particular syringe, including, but not limited to, information about the mechanical properties of a syringe (for example, material, length, diameter and/or volume) as well as information about the contents of the syringe (for example, fluid volume and/or composition). With the advent of new syringes, and especially prefilled syringes, the need to accurately encode and sense (or read) syringe configuration variables is heightened. A powered injector to control the injection procedure as a function of defined syringe configuration/injection parameters can use the information on syringe configuration. Moreover, a record of data associated with an injection procedure may be kept, for example, to track patient treatment history and/or to satisfy accurate billing and cost information requirements under managed health care. A record may be maintained of information such as the type of syringe used, the amount of contrast medium used, the type of contrast medium used, the sterilization date, the expiration date, lot codes, the properties of the contrast media, and/or other clinically relevant information. Such information can be recorded digitally for sharing with computerized hospital billing systems, inventory systems, control systems, etc.